stems

HIV antivirals

 plaque-forming units 
 measure the number of virus particles that cause plaques to form. 

PFUs are used to determine the
​viral titer of a sample.

In monocots, the vascular bundles are both distributed throughout the pith of the stem so they are unable to produce the concentric rings of xylem we call wood. Still, some may be "woody" like palms and bamboo. And not all dicots have woody stems. Tomato, carrot, and potato plants don’t have woody stems.

         coronavirus

Roots absorb water and minerals and transport them up to the stem. Roots also support a plant, anchor a plant and store food.

                                 random mutations alter viral genomes.
 RNA mutate more frequently than DNA genomes so RNA viruses evolve faster   than DNA viruses. RNA polymerase enzymes aren't able to correct mistakes.
 mutations which reduce infectivity produce attenuated strains.
 these strains don’t cause disease but can stimulate an immune response =   vaccine appropriate. ex. = polio vaccine.

 

​some mutations help viruses by:
   allow the virus to evade immune systems
   allow the virus to broaden its host range,
   allow the virus to infect a swider rfange of cell types ( expand tropism)
   allow the virus to more easily spread from one host to the next. 

 cool fungi info...

     hsv

review question:
      are viruses alive?         defend your answer. 

HIV is a retrovirus. It's nucleic acid is RNA. It infects a CD4+ lymphocyte then uses its reverse transcriptase enzyme to make DNA using the RNA code. Then, it uses another enzyme, integrase, to insert this DNA carrying the viral information genes into the DNA of the host cell.

review question:
   how might some random mutation help a virus?

xtra credit question:
   explain the steps in growing phage in a lab.

what is the use of a PFU?

     antivirals

     evolutionary adaptation #4:
                flowers and fruit

    herpes antivirals
 (acyclovir/ famciclovir/ valacyclovir)
 interfere with the synthesis of
​viral DNA. 

review question:
  how was the presence of viruses proven?

  fungi use enzymes to digest organic matter then they absorb the organic compounds to be used as a food source.  As natural recyclers, they return nutrients from dead organisms back into the soil.

Mosses, the simplest of plants, evolved from a filamentous green algae (protist) over 500 million years ago. As a primitive moss
consumed atmospheric carbon, oxygen concentration in the atmosphere increased permitting the evolution of modern life.

  fungi can often reproduce by the formations of
spores which are able to withstand cold and draught, forming a new fungal body when the conditions are right. 

         flowers

leaves

     pathogenicity of known viruses

review question:
   describe the general
structure of a virus

   giardia

viruses have different nucleic acids,
different shapes and sizes of their capsids, and they may or may not have a lipid envelope, obtained from its host cell, surrounding the capsid.

 and then there's pathogenic fungi...:(

should i get a booster?
https://blog.encompasshealth.com/2019/08/01/should-you-get-the-measles-vaccine/

some viruses are able remain dormant until reactivated = latency
A latent viral infection is a persistent infection...

rabies
lyssavirus

roots

  host cell/receptor
specificity:
​ligand of virus and receptor of host must be compatible

   fruit evolution

to exit the target cell:
enveloped viruses bud via the cell's membrane

​naked viruses usually cause  the cell to rupture but not always. 

 Is a virus different than a virion?
​           I've heard both words...

  people may get sick with prion diseases by eating or handling meat contaminated with prions. 

immunity to RSV is short term and generally not complete. Reinfection can occur so it is possible to get RSV multiple times although symptoms of subsequent infections are usually less severe.

viruses can carry
​either RNA or DNA

 angiosperm

       antiviral medications help the immune system fight infections by:
*blocking receptors so viruses can’t bind to and enter cells
*boosting the immune system 
*lowering the amount of active virus (viral load) which stops the                              progression of the virus. 

c-19 antiviral Paxlovid:
combination of  two drugs:
*nirmatrelvire inhibits the 3CL                        protease enzyme required for              viral replication
*ritonair: delays  nirmatrelvire                        from being broken down in                    the liver

 H = hemagglutinin  
 N = neuraminidase

xtra credit question:
   select any antiviral medication and explain how it works.

                lab techniques

growing
​bacteriophage 

​ colds are caused most commonly by rhinoviruses which are generally less severe

  As plants evolved, the sporophyte generation became dominant. In moss, the gametophyte (1n) generation is dominant. Starting with ferns, the sporophyte (2n) generation is dominant. higher plants have a microscopic gametophyte generation.

  Why do you think plants become
     2n dominant?
 What is the advantage?

Penicillin was discovered by Alexander Fleming after an uncovered
Petri dish in his lab became contaminated with mold. He saw that the bacteria near the mold had died. Fleming identified the mold as belonging to the Penicillium genus. 

  how are bacteria and viruses different/similar?

          How do viruses replicate?

ex: Corynebacterium diphtheriae can become capable of producing diphtheria toxin when infected by a phage carrying the toxin gene. 

spike protein = ligand

antigenic shift vs antigenic drift

enveloped 
​ animal virus

birdsfoot
​ trefoil

    "Viruses are naturally responsive to a number of biological stimuli, including pH, redox, and proteases. The viruses undergo physiochemical changes when exposed to these endogenous stimuli that allow behavior such as more efficient cargo delivery, increased stability, or modified intracellular trafficking."
​Stimulus-responsive viral vectors for controlled delivery   https://www.ncbi.nlm.nih.gov

   Kingdom Fungi

 ​ 45o million years ago, there was a supercontinent called
Pangaea
​ being formed by the shifting of the   Earth's plates. Life was mostly marine and the trilobites ruled the sea. Microbes clung to rocks, barely surviving in their semi aquatic habitat. From these protists, green mosses evolved, spreading from the   rocky edge of the water to dry land. The first true plants, mosses and their relations, spread and spread and over the next 40 million years, Pangaea was carpeted in moss. As carbon dioxide levels fell and O2 levels rose due to increased photosynthesis, the global temps dropped. Glaciers developed, weathering rocks into soil. 400 million years ago, the first vascular plants were able to take root, evolving into ferns. 

Viruses were first discovered by 
scientists in the late 19th century
experimenting with tobacco plants afflicted with

tobacco mosaic disease.
​It was found this disease could be transmitted by a liquid filtrate from one plant to another even after all bacteria from the extract had been removed. For years, scientists theorized these remaining infectious agents were just very small bacteria. It wasn't until electron microscopy came on the science in the mid 20th century that these infectious agents were proved to be novel parasites = viruses!  

Lytic cycle 
the virus takes control of a host cell and uses it to produce more viruses
The virus kills the host cell
This is also known as a virulent infection

ex:  sars-cov-2 spike
  protein specifically
  binds to ACE2
  receptor

RNA virus

review question:
   how are bacteria and virus similar? different?

ex: cholera toxin, produced by Vibrio cholerae, is due to the presence of a prophage, making phage conversion a key factor in the pathogenicity of this bacteria. 

           plant

   structure

 plant 

​tissue

 gymnosperm

prions

A virus consists of genetic material covered by a protein capsid. 
Virion is the extracellular, vector stage of an intracellular virus, which allows the transmission of a virus from an infected, host cell to another host cell. 

Tamiflu:
this antiviral inhibits the neuraminidase enzyme which is
essential in the replication and spread of the flu viruses. neuraminidase helps newly produced viruses to detach from one cell and infect others.  

         leaves

  fungi naturally produce antibiotics to kill or inhibit the growth of bacteria, limiting their competition in the natural environment.

Poliomyelitis is a highly contagious disease that can cause paralysis and sometimes death spread via aerosole
or contact with shedding feces.

   what are fungi?

review question:
   research one of the above viruses
or select another not discussed on this page.
Describe its pathogenicity, mode of transmission, vaccine efficacy
​(if available) and anything else interesting about the virus. 

2023: It is estimated that about 667 million people were infected with COVID-19  with 6.7 million deaths 

Bees use scent to find flowers.  They only see the color of a flower when they get close to them and are attracted to blue, yellow, white, purple and violet flowers. Violet is their fave.

         woody stems

  variola virus

  smallpox

DNA virus

Mumps, also a paramyxovirus, affects the parotid glands which are salivary glands below the jawline. 

review question:
   antiviral medications
fight infection three ways.
they are...

review question:
   explain how phage conversion is related to the lysogenic stage of a viral cycle. 

    How are viruses classified?

   flower evolution

      vascular tissue

 lysis

covid - 19 antivirals

   moss

   lytic vs lysogenic cycle of the bacteriophage

   trypanosomiasis
 (sleeping sickness):
      trympanosum

flowers and their pollinators have develpped a mutualistic relationship. flowers benefit by having their pollen distributed to other flowers and
pollinators benefit by feeding on the nectar that flowers produce. 

1. virus first hypothesis:
    viruses evolved along side cells from      basic polymers

2. regression hypothesis:
    viruses evolved from free-living cells

3. escapist/progressive hypothesis:
    viruses originated from RNA/DNA          that escaped from a host cell.

            ​Why aren't we sure?

   Viruses leave no fossil record...

     herpes

A vascular bundle is the transport system in vascular plants:
xylem moves water and mineral solutes
 up from the roots to the leaves while phloem carries photosynthetic products (glucose) down from the leaves to other parts of the plant. 

antigenic drift:
when a genome mutates, changes to spikes can occur. these minor changes = antigenic drift. they allow the virus to evade a quick antibody response by making the new strains just different enough to go unrecognized by the immune system. 
antigenic shift:
a major change to a viral genome can dramatically alter viral spikes = antigenic shift. this can lead to viral strains with new features, such as increased infectivity or expanded host range. think when avian and swine influenza strains “jumped species,” and started to infect humans. this can cause a pandemic because there's no preexisting immunity in the population

                  There is a sequence to viral replication:
​ 1. attachment: virus bonds to specific host cell via a ligand receptor match
2. import: virus enters host cell or injects genome into the host cell.
3. biosynthesis: new viral components are synthesized using host cell machinery 
​4. assembly: components are assembled into new virus
5. release: virus exit host cell via budding or lysis

 Pollen was first identified in the fossil record 140 million years ago. Pollen released plants from the requirement of water for fertilization.

review question:
   explain how the herpes virus
​ exhibits latency.

even bacteria can be infected by a virus...
a bacterial virus is called a 
bacteriophage
​or simply a
phage

 influenza

this status will determine the virus will infect and exit the target cell

​flowers 

Lysogenic cycle 
the virus's DNA integrates into the host cell's DNA so the viral DNA replicates along with the host DNA.
The host cell is not killed. This is also known as a non-virulent infection

    Where did viruses come from?

 budding

review question:
   how are enveloped virus and naked virus different? how does this difference affect how they infect cells?

viruses can be
"naked" or "enveloped"

​to infect the target cell:
enveloped viruses bind to the cell's surface receptors, then fuse their membrane with the cell's membrane.

​naked viruses bind to the cell's surface receptors, then digest the membrane and enter the cell intact.

   cold vs flu

   amoebic dysentery

50-85% death rate

 virus = poison

  people may get sick with prion diseases by eating or handling meat contaminated with prions. 

             Viruses are
    identified and classified 
​                       by:
*their phenotypes
*the nucleic acids they carry
*their host
*how they replicate
*the disease they cause. 

lichens are symbiotic composites of algae or cyanobacteria and fungi

  RSV

  The influenza virus can rapidly mutate and evolve

viruses are obligate intracellular parasites.
Even though they contain DNA or RNA and they evolve via the mutation of their nucleic acids, they are not cellular, they rely on the
​ metabolic actions of their host, and they  replicate only by hijacking their host cell machinery. As far as a response to stimuli...

         roots

  dominant   sporophyte

Cells in the vascular cambium divide toward the outside of the tree making bark and toward the center of the tree making wood. Wood is deposited each year in rings of growth.

 evolutionary adaptation #3:
            pollen and seeds

   malaria:
​plasmodium

     receptor blocking antivirals:
if an anti-viral med blocks a receptor on a cell to prevent a virus from binding, the normal function of the cell is inhibited because the normal ligand can't bind to the receptor. the cell, unable to receive a "to do" signal via ligand binding, can not carry out whatever activity  that ligand triggered. 

medications that block receptors are called antagonists. the bind to a specific receptor but don't activate it, rather, just keep any other protein from binding. 
an example of a receptor blocking med that is not an antiviral is a beta-blocker which block adrenaline receptors on heart cells in order to slow heart rate. 

here's a pubmed article about receptor blocking anti-virals...
​https://pmc.ncbi.nlm.nih.gov/articles/PMC6743247/

 Athlete's foot (and ringworm etc) is caused by a type of fungi called dermatophyte that normally live on the skin and nails and hair but only grow out of control when
their environment gets moist  and warm. ew. 

         stems

  what about Dr. Dorothy Hodgkin?

Measles was declared eliminated by t he CDC in the United States in 2000 when herd immunity was reached.

Antifungals target fungal cell wall/cell membranes.
When either is compromised, the fungal cell is degraded.
Azoles interfere the function of an enzyme required for  membrane function. Polyenes kill fungal cells by compromising the cell wall.

1918: It is estimated that about 500 million people or one-third of the world's population became infected with H1N1. The number of deaths was estimated to be at least 50 million  

xtra credit question:
   animal virus can be lab grown three ways. they are...

  When/how were viruses discovered?

Human immunodeficiency virus attacks the body's immune system. It may cause AIDS = acquired immunodeficiency syndrome.

viral mutations 

  besides being a pizza                    topping...

  Woody stems add height and girth           during every growing season.

        Ebola

Measles
is super contagious, spreading via aerosol from person to person. Infection can occur by being in a room where a person with measles has been 2 hours before you entered. 

  The first vascular plants evolved 420 million years ago. Vascular tissue permitted plants to grow up not just out, increasing their photosynthetic capabilities and range. 

naked bacteriophage

   fern

Respiratory syncytial virus (RSV)
​infects lung, throat, and nasal cells causing cold like symptoms and potentially bronchiolitis and pneumonia. It's transmitted as an aerosol and can survive on hard surfaces for several hours. RSV infected indivudlas remain 
contagious for 3 to 8 days. 

review question:
   virus can exit a cell two ways. describe both.

Most HIV drugs target viral enzymes

 flowers assist plant reproduction. A flowers color, scent and shape facilitates pollination, seed growth and seed dispersal. 

   The Alternation of Generations  
  describes the life cycle of plants. A haploid      (1n) multicellular gametophyte alternates  with a diploid (2n) multicellular sporophyte. 

amoeba invade the wall of the intestine causing ulcers, bleeding, and diarrhea

review question:
   explain the sequence of
​ viral replication.

   how did plants evolve?

   Kingdom Plantae

hiv

   What is the general ​structure of a virus?

review question:
   will an influenza virus infect the same cell as a pox virus? explain.

  evolutionary adaptation #1:           sporophyte dominance

​            Phage conversion
 occurs when a bacteriophage integrates its
 DNA into the bacterial chromosome, changing
 the inherent traits of the bacterium.   
 The phage DNA that's integrated into the
 bacterial chromosome is called a prophage.
 The phage genes can cause the bacteria to express
 new traits like virulence or toxin production.

 evolutionary adaptation #2:
​              vascular tissue

   As of 2020, approx. 148,000 species of fungi, mostly terrestrial, have been identified but the global biodiversity of fungi is still a mystery. Over 1.5 million living animal species have been described including 1 million insects. Estimations suggest there are more than 7 million animal species in total. There are an estimated 320,000 plant species in the world. 

Bats carry a lot of pollen in their fur compared to other pollinators and can fly long distances which benefits plants living in low densities habitats. They're attracted to flowers with a musty, rotten odor due to sulphur compounds. Bat flowers may be light-colored to be seen at night or a dull color if they only open at night. 

EBOV is transmitted via body fluids. It attacks the spleen and kidneys, killing cells that regulate
chemical/fluid balance and permit blood clotting.

Flowering plants and their pollinators are amazing example of
co-evolution

   DNA analyses showed in 1998 that fungi and animals last common ancestor was 1.538 billion years ago while plants and fungi last common ancestor was 1.547 billion years ago proving that fungi split from animals 9 million years after plants did. Fungi are more closely related to animals than to plants.

review question:
   prions freak me out!
explain what they are and list some reasons why they are so disturbing!

review question:
   how is the replication of an RNA virus different than that of a
DNA virus?

review question:
   list the criteria used to classify viruses.

virus are released from the host cell by either:
1. lysis: host cell destroyed
​2. budding: cell continues to produce virus

and a marvel of adaptation...

A viruses replication strategy depends on its type of nucleic acid

next up...
modifications of
​flowers stems roots leaves

ACE-2 = Angiotensin-converting enzyme 2 is an enzyme of the renin–angiotensin–aldosterone system (RAAS)
AND
is a receptor on cell surfaces through which SARS-CoV-2 enters the host cells.
ACE-2 is found in heart, kidneys, and lungs cells. 
What does ACE-2 normally do?
​---------->

 animal viruses
​are grown in the lab using live animals, the embryos in eggs or cell cultures 

    What are viruses?

  dominant   sporophyte